@mixin layered-coins($color) {
  color: $color;
  background-color: $color;

  $shadows: ();

  @for $idx from 0 to 4 {
    $offset: $idx * 34px / 2;
    $offset-shadow: $offset + 2;
    $shadows: map-merge($shadows, (
      layer-#{$idx}: 0 $offset $color,
      shadow-#{$idx}: 0 $offset-shadow 3px rgba(0, 0, 0, .3)
    ));
  }

  box-shadow: map-values($shadows);
}